• Journal of Powder Materials
• /
• v.10 no.1
• /
• pp.15-20
• /
• 2003

Hybrid $A1_2O_3-TiC$ ceramic particle reinforced 6061 and 5083 Al composite powders were prepared by the combination of twin rolling and stone mill crushing process, followed by consolidating processes of cold compaction, degassing and hot extrusion. The composite bar consists of lamellar structure of ceramic particle rich area and matrix area, in which the hybrid was decomposed into each TiC of about $3-4\mutextrm{m}$ and $AI_2O_3$ particles of about $1-2\mutextrm{m}$ in diameter. It also found that fine $Mg_2Si$ precipitates of about 30 nm were embedded in the matrix, which have grains of about 3 $\mutextrm{m}$. Higher UTS was measured at the 5083 composite bar compared to the conventionally fabricated composite, due to again refinement effect by the rapid solidification. No particle was shown to form in the interface between the matrix and reinforcement, whereas carbon was diffused into the matrix.

• Agricultural and Biosystems Engineering
• /
• v.2 no.1
• /
• pp.7-14
• /
• 2001

A rice mill plant with a capacity of 3 t/h was constructed with automated facilities at Chonnam National University. A simulation model was developed with SLAMSYSTEM for evaluation and improving the rice mill process. The developed model was validated in the views of hulling efficiency, milling efficiency, milled rice recovery, other materials produced, at bottlenecks in the processes. The results of hulling efficiency, milling efficiency, milled rice recovery in the simulation were, respectively, 81.1%, 89,5%, and 73.1%, while those of the actual mill plant were 81.5%, 90.2%, and 73.5%. The simulation results including the rates of other materials(chaff, bran, broken rice, stone, etc) produced in the processes were almost similar with those of the actual process. In the simulation the bottlenecks were found out in the process for separating brown rice and sorting colored rice. These phenomena also appeared in the actual process. It needed to increase the hourly capacities of the brown rice separator and the rice color sorter. As the developed model could well express the automated rice mill plant, it could be used for designing and improving rice mill plants.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11b
• /
• pp.378-387
• /
• 2000

A rice mill plant with a capacity of 2.5 ton/hr was constructed with automated facilities at Chonnam National University. A simulation model was developed with SLAM SYSTEM for evaluating and improving the rice mill plant. The developed model was validated in the views of hulling efficiency, milling efficiency, milled rice recovery, other materials produced, and bottlenecks in the processes. The results of hulling efficiency, milling efficiency, milled rice recovery in the simulation were, respectively, 81.1%, 89.5%, and 73.1%, while those of the actual mill plant were 81.5%, 90.2%, and 73.5%. The simulation results including the productivity of other materials(chaff, bran, broken rice, stone, etc) produced in the processes were almost similar with those of the actual process. In the simulation the bottlenecks were found out in the processes of separating brown rice and of sorting colored rice. These phenomenon also appeared in the actual process. It needed to increase the hourly capacity of the brown rice separator and the rice color sorter. As the developed model could well express the automated rice mill plant, it could be used for designing and improving rice mill plants. In addition, an alternative model needed to be developed for the system control more accurately and for increasing the rice quality.

• Journal of Technologic Dentistry
• /
• v.35 no.1
• /
• pp.57-64
• /
• 2013

Purpose: Waste parts of zirconia blocks and powders were remained after CAD/CAM process. In order to make these residual zirconia fit for practical use, zirconia single cores were produced by drain casting process. Methods: Remained zirconia blocks were reduced to powders with zirconia mortar, and screened with 180 mesh sieve. Zirconia slip was prepared from waste parts of zirconia by ball milling. Plaster molds for forming cores by slip casting were also prepared. Formed cores were removed from mold after partial drying. Dried cores were biscuit fired at $1,100^{\circ}C$ for 1hour. Biscuit fired cores were treated with tools to control the fitness and thickness. Finished cores were $2^{nd}$ fired at $1,500^{\circ}C$ for 1hour. Microstructure of cross section of core was observed by SEM. Results: When mill pot was filled with 100g of zirconia and alumina mixed powder, 300g of zirconia ball, and 180g of distilled water, the optimum slip for drain casting was obtained. Gypsum plaster for ceramic forming was more suitable then yellow stone plaster for casting process. SEM photograph showed the microstructure of fully dense with uniform grain size of zirconia and well dispersed alumina grains into the zirconia matrix. Conclusion: Zirconia single cores were produced by drain casting process. Drain casting is useful process to make these residual zirconia fit for practical use. Further study will be focused on the preparation of the bridge type cores by casting.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.38 no.3
• /
• pp.83-91
• /
• 2020

The purpose of this study is to examine the process of formation of modern gardens. Based on the analysis of the process of formation and transformation of the Jemulpo in Incheon and the details of the modern garden construction. The results are as follows; First, the formation of the Incheon Residence Site began in 1876 with the signing of the Joseon-Japan Treaty. Jemulpo used to be a desolate fishing village in the past, but after its opening in 1881, the Japanese settlement, Chinese settlement, and the general foreign settlement were formed. After that, Japan reclaimed the southern mudflats and expanded the theire settlement area, and advanced to the Joseon area(currently Sinheung-dong). In Japanese colonial era, modern Japanese urban landscapes were transplanted into the settlement area, centering on the Japanese modern gardens were distributed in the area around the center of the settlement area. Second, after examining the process of creating the garden for the Rikidake villa, Japanese Rikidake purchased a site for an orchard in Uri-tang, who was a major landowner in Incheon, to create the garden. At the time of Rikidake's residence, the garden was very large, measuring about 3,000 pyeong, and after liberation, it was acquired by Incheon City and used as Yulmok Children's Library. It was known as a rich village at the time of the opening of the port, and a garden was located at the highest point in Yulmok-dong, making it easy to see the Incheon Port area. Also, a spot located about 300 meters away from Rikidake's rice mill may have affected the location selection. Third, today's Rikidake villa has a Japanese-style house on a trapezoidal site, with a garden of about 990 square meters on the south side. Currently, it is possible to enter from the south and from Yulmok Children's Park in the north, but in the past, the main direction of the house was to view the Incheon Port, settlement area, and the Rikidake Rice Mill, so the house was located in front of the garden. The garden is a multi-faceted style with stone lanterns, tombstones, garden stones, and trees placed on each side, and is surrounded by arboreal plants such as attention, strobe pine, and maple trees, as well as royal azaleas. The view from the inside of the house was secured through shrub-oriented vegetation around the house.